Break detector and shut down means



Feb. 25, 1969 w. 'r. WINDLEY 3,429,491

BREAK DETECTOR AND SHUT DOWN MEANS Filed May 8, 1967 29 FIG. P l3 OTHER POSITIONS I II INVENTOR WILLIAM THOMAS WINDLEY ATTORNEY United States 3,429,491 BREAK DETECTOR AND SHUT DOWN MEANS William Thomas Windley, Seaford, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed May 8, 1967, Ser. No. 636,982 US. Cl. 226-11 Int. Cl. B65h 25/22 ABSTRACT OF THE DISCLOSURE means and activating an alarm system upon sensing reduced power requirements for the advancing roll motor due to a strand break.

Background of the invention This invention relates to the handling of strands advancing continuously from an operating source and, more particularly, to an apparatus for stopping the advancing means in a strand handling machine upon the occurrence of a strand break and for giving a selective indication of the break location.

The term "strand" as used herein is intended to include either a single filament, a bundle of such filaments or the threads, yarns, narrow webs and the like produced from filaments or staple fibers.

In a spinning process, wherein a filament forming material is extruded from a spinneret, the extrusion is normally not stopped when a defective condition occurs in the handling steps which follow extrusion. Such defects are usually in the form of complete breakage of a filament bundle or of a low number of filaments in the bundle being handled, resulting in wraps forming on advancing rolls of the downstream handling equipment. Since it is customary to.have a single operator patrol a multiplicity of positions, such wrap conditions may go unnoticed for a considerable period of time with resultant damage to the handling equipment. In some instances, it has been the practice to employ yarn contact sensing elements to detect strand breaks and to actuate stop motion equipment or cut-down devices, thereby interrupting downstream delivery from a given source to prevent wrap buildup. While these devices are operable. the yarn contact elements are trouble spots in that they wear rapidly and degrade yarn being sensed. Additionally, these yarn contact elements are insensitive to a low number of filament breaks in a bundle of filaments being handled.

Summary of the invention It is accordingly the object of this invention to provide an apparatus for sensing and indicating a break in a strand material and stopping the strand advancing means that does not rely on contacting the advancing strand.

This object is accomplished, in a strand handling machine that includes first and second advancing rolls driven by respective electric motors, by an apparatus for detecting a break in a strand advancing between the rolls. The apparatus includes a power sensor having input terminals and output terminals. The input terminals are connected to the second advancing roll motor and the power sensor provides a signal at its output terminals proportional to the power input to the second advancing 3,429,491 Patented Feb. 25, 196 9 roll motor. Switching means connected between the output terminals of the power sensor and the first advancing Brief description of the drawings FIGURE 1 is a schematic showing of one position of a mulli-position strand drawing machinein conjunction with electrical sensor control means; and

FIG. 2 is an electrical schematic showing of the power sensor in combination with the draw roll motor.

Description of the preferred embodiment Referring to FIG. 1, one position of the strand handling machine chosen for purposes of illustration is a filamentary threadline drawing machine and includes generally, as components, an equipment frame 10, a first advancing roll or a feed roll 14 directly coupled to synchronous motor 18, a separator roller 16 in spaced relationship to feed roll 14, a second advancing roll or a draw roll 20 directly coupled to synchronous motor 24 on frame 10, a separator roller 22 in spaced relationship to the draw roll 20, a pair of yarn guides 12 and 26 and a power sensor 28 electrically connected to the power lines between three-phase power source 58 and motor 24. The output terminals 42 and 44 of power sensor 28 are connected to a meter relay 46, that, in turn, is electrically connected to power source 52 and relay coil 50. Relay 50 carries contactors 54 which are connected in power supply lines connecting power source 71 with audio and visual alarms 56 and 57, respectively, and in power supply lines connecting power source 58 with motor 18.

Referring again to FIG. 1, filamentary threadline 11 is advanced continuously from a spinneret 13 through a fixed guide 12 and around positively driven feed roll The yarn is then passed through guide 26 and traverse guide 27 onto bobbin 29. Bobbin 29' and spinneret 13' are shown as representative of another position in a multl-position machine. As is well known in the art of yarn drawing, a portion of the total power consumed by the draw roll motor 24 is related to the restraining yarn tensions bet-ween draw roll motor 24 and feed roll motor 18. Such tension related power can be readily determined by comparing load vs. no load conditions on motor 24 for various draw ratios and is monitored by power sensor 28 which produces an output signal at terminals 42, 44 which is in turn indicated by meter relay 46. Meter relay 46 is adjusted so that, under a selected draw ratio load conditions of motor 24, the set of contacts 48 of the meter relay 46 are normally closed, thus energizing relay coil 50 through power source 52. When relay 50 is energized, contacts 54 carried by relay 50 are closed in the power feed lines between motor 18 and power source 58 with one contact open in power feed line connecting power source 71 with audio alarm 56 and visual warning light 57.

In FIG. 2, power sensor 28 is shown connected through input terminals 30, 31, 32, 33, 34 to 3-phase 220 v. power source 58 supplying power to motor 24. Numeral 61 generally designates a Hall effect device which includes a Hall plate '60 disposed within the air gap of an iron core 62. Coils 64, 80 are placed around core 62 and each is connected in series with one phase of power supply 58 to provide magnetizing current I that are in phase with line current. The primary winding 63 of transformer 66 is connected across one phase of voltage: source 58 with the secondary winding 65 connected to terminals 67 and 69 of Hall plate 60 to provide a control current I that is proportional to and in phase with line voltage. D.C. supply 68 is a bias voltage paralleled by potentiometer 70 and connected in series with Hall plate terminal 72 and output terminal 42 to provide an incremental adjustment to the output of the Hall plate at output ter minals 42, 44.,

It is well known that when a current I flows in a Hall effect device and a magnetic field 76 is applied at right angles to the current flow, an electrical potential known as Hall voltage (V is generated which is perpendicular to both the direction of the current flow and the magnetic field. This potential appears at the mid-points of the lateral faces of plate 60 at which points electrodes 72 and 74 have been connected. This potential is measured by meter relay 46 (FIG. 1), e.g., Model 202 manufactured by Assembly Products, Inc. Since the control current L, is proportional to and in phase with the line voltage 58 and the magnetizing current I is in phase with the line current, the Hall voltage output V (72, 74) is proportional to the power input to motor 24. The coils 64, 80 connected in series with two phases of the power supply provide a linear output regardless of phas ing of lead polarity.

In operation the loss of threadline 11 of the breakage of one or more filaments in the bundle causes a decrease in tension related power to motor 24. This decrease in power is sensed by Hall device 61 in the form of a reduced output at terminals 42, 44. This reduced output is indicated by meter relay 46 and. contacts 48 are opened, which, in turn, break the circuit between the 110 v. sup ply 52 and relay coil 50. Deenergizing coil 50 displaces contacts 54 to the position 54 shown in phantom. This opens the 220 v. power supply to motor 18. Additionally, alarm light 57 and audio alarm 56 are energized from 110 v. source 71 to notify the operator that a position is down. A switch 51 (FIG. 1) is employed to bypass open contacts 48 so that motor 18 will be operative during stringup procedure. After threadline 1.1 is passed around roll 24 and through guide 26, switch 51 is opened and the power sensor control is again operative.

The Hall device 61 is sufiiciently sensitive to detect not only the complete loss of threadline 11 but also the breakage of a low number of filaments in a multifilament threadline. It is recognized that in. the illustrated embodiment if a low number of filaments in a multifilament bundle should break the shutting down of the feed roll motor will cause the remainder of the threadline to be pulled apart by the continued operation of the draw roll motor, which could be harmful to the handling equipment. To overcome this, it is contemplated that the solenoid 50 may be connected to and used to actuate a threadline cutdown device of the type disclosed by Edwards in US. Patent 3,090,268.

While the invention has been described in conjunction with equipment wherein one or more strands are drawn between two positively driven rolls, it should be under stood that in strand handling equipment where more than two driven advancing rolls are used, power sensors could be connected to each roll motor to sense various proc essing conditions and then in turn function as stop mo= tion devices for individual motors or various combinations of these motors.

It should also be noted that alternative to meter relay 46, solid state switching equipment is readily adaptable for detecting changes in the output of the power sensor and initiating operation of switching means to shut down advancing roll motors and to positionally indicate fault locations. 7

It is apparent that many changes and modifications may be made to the disclosed apparatus without departing from the spirit of the present invention which is intended to be limited only by the scope of the appended claims.

What is claimed is:

'1. In a strand handling machine that includes first and second advancing rolls driven by respective electric motors, an apparatus for detecting a break in a strand advancing betwen the rolls and shutting down the first advancing rol-l motor, said apparatus comprising:

'(a) a power sensor having input terminals and output terminals, said input terminals being connected to the second advancing roll motor, said sensor providing a signal at said output terminals proportional to the power input to the second advancing roll motor; and

-(b) switching means connected between the output terminals of the power sensor and the first advancing roll motor for de-energizing t-he first advancing roll motor upon a change in signal from the power sensor due to a change in power input to the second advancing roll motor.

2. The apparatus of claim 1 wherein is provided a signalling means connected to said switching means for signalling a strand break, said signalling means being operative upon de-energization of said first advancing roll motor.

3. The apparatus of claim 1, wherein said sensor is a Hall effect device,

4. In a strand drawing machine having a plurality of positions, each including a feed roll and a draw roll driven by respective three-phase electric motors, an apparatus for detecting the breaking of one or more filaments in a bundle of filaments being drawn between the rolls, shutting down the feed roll motor, and selectively indicating the positional location of the filament break, said apparatus comprising:

'(a) a Hall efiect device having input terminals and output terminals, said input terminals being connected to the draw roll motor, said Hall effect device providing a signal at said output terminals proport-ional to the power input to the draw roll motor;

(b) means connected between the output terminals of the Hall effect device and the feed roll motor for tie-energizing the feed roll motor upon a decrease in signal from the Hal-l elfect device due to a decrease in power input to the draw roll motor; and

(c) signalling means connected to said means for deener-gizing the feed roll motor for signalling a filament break and selectively indicating the positional location of the break, said signalling means being operative upon de-energization of said feed roll motor.

References Cited UNITED STATES PATENTS 3,361,314 V1968 Gitlr 226 1l ALLEN N. KNOWLES, Primary Examiner.

US. Cl. X;R. 

